The present invention generally relates to a transmitter and, more particularly, to a radio frequency identification (RFID) transmitter having a range-variable antenna matching function for remote control.
RFID technology has been widely used various products such as be used to remotely control various consumer electronic products, for example, stereo systems, digital video disc (DVD) players and game consoles, etc. An RFID control may have to verify an electronic product via antenna matching to establish a communication channel. However, an RFID remote control may sometimes inevitably match unintended electronic products. FIG. 1 is a schematic diagram illustrating an RFID remote control and a plurality of electronic devices. Referring to FIG. 1, electronic devices 21, 22, 23, 24 and 25 may be located at different distances from the RFID remote control 1. The transmitter (not shown) resided in the RFID remote control 1 may have enough emitting power so that each the electronic devices 21, 22, 23, 24 and 25 may be able to receive RF signals from the RFID remote control 1. Accordingly, not only the target electronic device, for example, product 23 but the other devices 21, 22, 24 and 25 may receive the RF signal.
It may therefore be desirable to have a remote control which is equipped with a range-variable transmitter to achieve the antenna matching with the target device.